Laboratory production of buffalo (Bubalus bubalis) embryos

The potential role of the KFG and KITLG proteins in preventing granulosa cell apoptosis in Bubalus bubalis

BACKGROUND

The dynamics of mammalian follicular development and atresia is an intricate process involving the cell-cell communication mediated by secreted ovarian factors. These interactions are critical for oocyte development and regulation of follicular atresia which in part are mediated by keratinocyte growth factor (KGF) and kit ligand (KITLG), but their roles in the regulation of apoptosis in buffalo granulosa cells have not yet been defined. During mammalian follicular development, granulosa cell apoptosis triggers the atresia so ~ 1% follicles reach the ovulation stage. In the present study, we used buffalo granulosa cells to examine the effects of KGF and KITLG in apoptosis regulation and investigated potential mechanism on Fas-FasL and Bcl-2 signaling pathways.

RESULT

Isolated buffalo granulosa cells were cultured with KGF and KITLG proteins using different doses (0, 10, 20, and 50 ng/ml) independently or in combination. Expression analysis for both anti-apoptotic (Bcl-2, Bcl-xL, and cFLIP) and pro-apoptotic (Bax, Fas, and FasL) genes at transcriptional levels were carried out by real-time PCR. Upon treatments, expression levels of anti-apoptotic genes were significantly upregulated in a dose-dependent manner, showing an upregulation at 50 ng/ml (independently), and at 10 ng/ml in combination. Additionally, upregulation of growth-promoting factors, bFGF, and α-Inhibin was also observed.

CONCLUSIONS

Our findings suggest the potential roles of KGF and KITLG in determining granulosa cell growth and regulating apoptosis.

Effect of Passage Number of Conditioned Medium Collected from Equine Amniotic Fluid Mesenchymal Stem Cells: Porcine Oocyte Maturation and Embryo Development

Oocyte in vitro maturation (IVM) is the most important first step in in vitro embryo production. One prerequisite for the success of IVM in oocytes is to provide a rich culture microenvironment that meets the nutritional needs of developing oocytes. We applied different equine amniotic fluid mesenchymal stem cell conditioned medium (eAFMSC-CM) from passages 7, 18, and 27 to porcine oocytes during IVM to determine its effects on oocyte development and subsequent embryo development, specifically. The eAFMSC-CM from passage 7 (eAFMSC-CMp7) has a considerable impact on 9 genes: BAX, BCL2, SOD2, NRF2, TNFAIP6, PTGS2, HAS2, Cx37, and Cx43, which are associated with cumulus cell mediated oocyte maturation. GSH levels and distribution of mitochondrial and cortical granules were significantly increased in oocytes incubated with eAFMSC-CMp7. In addition, catalase and superoxide dismutase activities were high after IVM 44 h with eAFMSC-CMp7. After in vitro fertilization, blastocyst quality was significantly increased in the eAFMSC-CMp7 group compared to control. Lastly, the antioxidant effect of eAFMSC-CMp7 substantially regulated the expression of apoptosis, pluripotency related genes and decreased autophagy activity in blastocysts. Taken together, this study demonstrated that the eAFMSC-CMp7 enhanced the cytoplasmic maturation of oocytes and subsequent embryonic development by generating high antioxidant activity.

Transcriptome comparisons detect new genes associated with apoptosis of cattle and buffaloes preantral follicles

Background

To develop new breeding technology to improve the breeding ability of bovine, it is the development trend to find the main reason for the occurrence of atresia in these organisms. Transcriptomes of small (100–120 μm) and large (200–220 μm) preantral follicles from cattle and buffalo ovaries were evaluated in vivo and in vitro to understand the transcriptional modulation in preantral follicles that leads to the phenomenon of atresia.

Methods

The preantral follicles were checked as dead, damage, or live follicles in vivo and in vitro by using trypan blue then bisbenzimide and propidium iodine. Transcriptomes of small (100–120 μm) and large (200–220 μm) preantral follicles of cattle and buffalo were evaluated in vivo and in vitro by microarray and RT-PCR. Healthy preantral follicles were selected based on staining results, and then RNA was extracted from them.

Results

The viability percentage of preantral follicles in cattle was higher (26.7% and 20%) than buffalo (10%) in vivo and in vitro, respectively. According to the microarray data analysis for cattle preantral follicles, only eleven genes were detected corresponding to five upregulated and six downregulated in large size (200–220 μm) compared to small (100–120 μm) size preantral follicles, while in buffalo, 171 genes were detected (92 upregulated and 79 downregulated) in large size compared to small preantral follicle size. The results of RT-PCR of the selected genes (FASTKD1, BAG2, RHOB, AGTR2, MEF2C, BCL10, G2E3, TM2D1, IGF-I, IGFBP3, PRDX3, and TRIAP1) validated the microarray results. In conclusion, the data of gene expression showed significant differences between small and large sizes in both buffalo and cattle preantral follicles.

Conclusion

Apoptotic genes were upregulated in the large preantral follicle compared with the small preantral follicles. Moreover, the expression level of these apoptotic genes was significantly upregulated in buffalo than in the cattle. Most of these genes were significantly upregulated in the large buffalo preantral follicle compared with the small size. However, anti-apoptotic genes were upregulated in large cattle preantral follicle and downregulated in large buffalo preantral follicle.

Butylparaben Is Toxic to Porcine Oocyte Maturation and Subsequent Embryonic Development Following In Vitro Fertilization

Parabens are widely used in personal care products due to their antimicrobial effects. Although the toxicity of parabens has been reported, little information is available on the toxicity of butylparaben (BP) on oocyte maturation. Therefore, we investigated the effects of various concentrations of BP (0 μM, 100 μM, 200 μM, 300 μM, 400 μM, and 500 μM) on the in vitro maturation of porcine oocytes. BP supplementation at a concentration greater than 300 μM significantly reduced the proportion of complete cumulus cell expansion and metaphase II oocytes compared to the control. The 300 μM BP significantly decreased fertilization, cleavage, and blastocyst formation rates with lower total cell numbers and a higher rate of apoptosis in blastocysts compared to the control. The BP-treated oocytes showed significantly higher reactive oxygen species (ROS) levels, and lower glutathione (GSH) levels than the control. BP significantly increased the aberrant mitochondrial distribution and decreased mitochondrial function compared to the control. BP-treated oocytes exhibited significantly higher percentage of γ-H2AX, annexin V-positive oocytes and expression of LC3 than the control. In conclusion, we demonstrated that BP impaired oocyte maturation and subsequent embryonic development, by inducing ROS generation and reducing GSH levels. Furthermore, BP disrupted mitochondrial function and triggered DNA damage, early apoptosis, and autophagy in oocytes.

In vitro embryo production in buffaloes: from the laboratory to the farm

Transvaginal follicular aspiration technique together with in vitro embryo production are the biotechnological alternatives currently available to support genetic improvement breeding programs in buffalo species. However, aspects related to animal management, lack of knowledge of the metabolic needs and biochemical peculiarities of gametes and embryos, as well as the reproductive physiology characteristics have hampered progress in the results. Despite the low availability of good quality oocytes collected after OPU in donors as a physiological characteristic of buffalo species, high rates of oocyte maturation, modest embryo cleavage, blastocyst production and pregnancy rates after transvaginal embryo transfer in recipients could be obtained in buffalo in vitro embryo production programs. The results of implementing an in vitro embryo production program in buffaloes in the northern region of Pará state, Brazil, and results published by other groups demonstrate the feasibility of implementing this biotechnology in the routine of breeding programs. Nevertheless, in order to achieve better and consistent results, it is necessary to deepen the knowledge on the peculiarities of reproductive biology in this specie. Selection of donor animals based on ovarian size and ovarian follicular reserve and on the rate of blastocyst production is presented as an effective alternative to increase the efficiency of the in vitro embryo production technique applied to the buffalo species.

Sodium fluoride exposure exerts toxic effects on porcine oocyte maturation

Excessive long-term fluoride intake is associated with several health problems, including infertility. However, limited information is available on the toxic effects of fluoride exposure on the female reproductive system, especially oocyte maturation. In this study, we investigated the toxic effect of sodium fluoride (NaF) exposure on porcine oocyte maturation and its possible underlying mechanisms. Our results showed that NaF exposure during porcine oocyte maturation inhibited cumulus cell expansion and impaired polar body extrusion. Cell cycle analysis showed that NaF exposure blocked meiotic resumption, disturbed spindle dynamics, disrupted chromosome separation, and increased aneuploidy in porcine oocytes. Moreover, NaF exposure disturbed mitochondrial function, triggered DNA damage response, and induced early apoptosis in porcine oocytes. NaF exposure also induced oxidative stress, decreased GSH level, and increased cathepsin B activity in and impaired the further development potential of porcine oocytes, as indicated by a decrease in blastocyst formation rate, increase in apoptosis, and inhibition of cell proliferation. Together, these results indicate that NaF exposure impairs the maturation capacity of porcine oocytes by inhibiting cumulus cell expansion, disturbing cytoskeletal dynamics, and blocking nuclear and cytoplasmic maturation, thus decreasing the quality and affecting the subsequent embryonic development potential of porcine oocytes.

Follicle-stimulating hormone-induced rescue of cumulus cell apoptosis and enhanced development ability of buffalo oocytes

The effect of follicle-stimulating hormone (FSH) on apoptotic status of cumulus cells, expression of proapoptotic and antiapoptotic genes, and development rate of in vitro fertilization-produced buffalo embryos were investigated. FSH supplementation in in vitro maturation-medium resulted in a dose-dependent reduction in the expression of proapoptotic genes namely, BCL2-associated X protein (BAX), cytochrome c, and caspase-3 and increase in the expression of antiapoptotic genes such as B-cell lymphoma 2 (BCL2) and X-linked inhibitor of apoptosis protein (XIAP) in cumulus cells of mature oocyte. Cumulus expansion, oocyte maturation, cleavage, and blastocyst development rates were significantly higher (P < 0.05) in 5 and 10-μg/mL FSH-supplemented groups as compared with control. Significant increase in the expression of FSH receptor messenger RNA was also found with 5 and 10-μg/mL FSH (P < 0.05). Terminal deoxynucleotidyl transferase dUTP nick end labeling assay confirmed that the population of apoptotic cumulus cells of matured oocytes was reduced in the FSH-treated groups as compared with control (P < 0.05). In conclusion, our data suggest that FSH may attenuate apoptosis in cumulus cells via mitochondria-dependent apoptotic pathway by increasing XIAP expression, resulting in a more favorable ratio of BCL2/BAX expression and decreasing the cytochrome c and caspase-3 expression, eventually contributing to developmental competence of oocytes. The information generated will help in improving the in vitro embryo production program in buffalo.

A review of recent developments in buffalo reproduction - a review

The buffalo is an important livestock resource in several countries of South Asia and the Mediterranean regions. However, reproductive efficiency is compromised due to known problems of biological and management origins, such as lack of animal selection and poor nutrition. Under optimal conditions puberty is attained at 15 to 18 months in river buffalo, 21 to 24 months in swamp buffalo and is influenced by genotype, nutrition, management and climate. However, under field conditions these values deteriorate up to a significant extant. To improve reproductive efficiency, several protocols of oestrus and ovulation synchronization have been adopted from their use in commercial cattle production. These protocols yield encouraging pregnancy rates of (30% to 50%), which are comparable to those achieved in buffaloes bred at natural oestrus. The use of sexed semen in buffalo heifers also showed promising pregnancy rates (50%) when compared with conventional non-sexed semen. Assisted reproductive technologies have been transferred and adapted to buffalo but the efficiency of these technologies are low. However, these latest technologies offer the opportunity to accelerate the genetic gain in the buffalo industry after improving the technology and reducing its cost. Most buffaloes are kept under the small holder farming system in developing countries. Hence, future research should focus on simple, adoptable and impact- oriented approaches which identify the factors determining low fertility and oestrus behaviour in this species. Furthermore, role of kisspeptin needs to be explored in buffalo.

Developmental potency of pre-implant parthenogenetic goat embryos: effect of activation protocols and culture media

The developmental potency of pre-implant parthenogentic goat embryos were compared under two chemical activation protocols in three different culture media groups. The in vitro matured oocytes were chemically activated by two protocols viz. P1 (CB-CHX-6DMAP) and P2 (Ca-CHX-6DMAP). The activated oocytes under both the protocols were developed in three culture media, viz. modified synthetic oviductal fluid (mSOF), research vitro cleave medium (RVCL), and RVCL-Blast. While comparing the developmental potential of activated oocytes, it was observed that the oocytes activated under P2 protocol pooled over three culture media group producing significantly higher mean cleavage rate (43.2±0.9 vs 40.6±1.5), blastocyst development (16.4±1.1 vs 12.6±0.8), and blastomere count (120.7±4.7 vs 113.2±4.1) as compared to P1 protocol. The comparison of effect of culture media pooled over protocol groups revealed that the mean cleavage rate observed under RVCL-Blast (44.8±1.3) and RVCL (45.3±0.5) were significantly higher (P≤0.01) than mSOF (35.8±1.2). However, the mean blastocyst development observed under RVCL-Blast group (18.8±3.2) was significantly higher than RVCL (14.0±0.8) and mSOF (10.8±0.4). Similarly, the mean blastomere count under RVCL-Blast group (136.0±3.7) was significantly higher (P≤0.01) than RVCL (114.7±1.0) and mSOF (100.2±0.5) groups. The semiquantitative RT PCR analysis showed the expression of pro-apoptotic caspase 3 gene in P1 and anti-apoptotic Mcl-1 gene in P2. This study concludes that the activation protocol P2 and embryo cultured under RVCL-Blast group were optimum for chemical activation and culture medium, respectively.

Expression pattern of pluripotent markers in different embryonic developmental stages of buffalo (Bubalus bubalis) embryos and putative embryonic stem cells generated by parthenogenetic activation

In this study, we describe the production of buffalo parthenogenetic blastocysts and subsequent isolation of parthenogenetic embryonic stem cell (PGESC)-like cells. PGESC colonies exhibited dome-shaped morphology and were clearly distinguishable from the feeder layer cells. Different stages of development of parthenogenetic embryos and derived embryonic stem cell (ESC)-like cells expressed key ESC-specific markers, including OCT-4, NANOG, SOX-2, FOXD3, REX-1, STAT-3, TELOMERASE, NUCLEOSTEMIN, and cMYC. Immunofluorescence-based studies revealed that the PGESCs were positive for surface-based pluripotent markers, viz., SSEA-3, SSEA-4, TRA 1-80, TRA 1-60, CD-9, and CD-90 and exhibited high alkaline phosphatase (ALP) activity. PGEC cell-like cells formed embryoid body (EB)-like structures in hanging drop cultures and when cultured for extended period of time spontaneously differentiated into derivatives of three embryonic germ layers as confirmed by RT-PCR for ectodermal (CYTOKERATIN8, NF-68), mesodermal (MSX1, BMP-4, ASA), and endodermal markers (AFP, HNF-4, GATA-4). Differentiation of PGESCs toward the neuronal lineage was successfully directed by supplementation of serum-containing media with retinoic acid. Our results indicate that the isolated ESC-like cells from parthenogenetic blastocyst hold properties of ESCs and express markers of pluripotency. The pluripotency markers were also expressed by early cleavage-stage of buffalo embryos.

Quantification, morphology and ultrastructure of preantral follicles of buffalo (Bubalus bubalis) foetuses

The objective of this study was to determine the number, morphology and ultrastructure of preantral ovarian follicles of buffalo (Bubalus bubalis) foetuses at different ages. Quantification revealed number of primordial, primary and secondary follicles of 48,857 ± 17,506, 26,000 ± 20,452, 18,428 ± 10,875 and 18,375 ± 19,690, 225 ± 349, 326 ± 288 at 12-34 cm and 35-60 cm crown rump length (CRL), respectively. Follicular diameter values were 28.9 (± 3.4), 34.7 (± 5.9) and 59.4 (± 12.6) μm; oocyte diameters were 21.7 (± 2.8), 24.3 (± 3.4) and 33.0 (± 7.7) μm, and the numbers of follicular cells in the follicle equatorial section were 7.1 (± 1.4), 12.0 (± 2.4) and 13.8 (± 2.4) for primordial, primary and secondary follicles, respectively. The primordial follicle consisted of an oocyte surrounded by a layer of flattened follicular cells with a normally eccentric oocyte nucleus. Dispersed Golgi complex, smooth endoplasmic reticulum, rounded mitochondria and several lipid vesicles were observed in the cytoplasm and cell junctions between the follicle cell membranes and the oocyte. This work describes the number, morphometry and ultrastructure of preantral follicles of buffalo foetuses, concluding that folliculogenesis is established between 8 and 34 cm CRL and that follicle number varies individually and according to age and that further studies are needed in this species.

Factors affecting laboratory production of buffalo embryos: a meta-analysis

In vitro fertilization (IVF) provides an excellent and inexpensive source of embryos for carrying out basic research on developmental physiology, farm animal breeding, and for commercial applications. Meta-analysis of the results from different publications rather than a narrative review may provide a current status of this technology in buffalo (Bubalus bubalis). In order to gain an idea of the factors affecting the IVF in buffalo, a review of the various studies conducted on buffalo IVF and a meta-analysis of their findings was undertaken. More than 100 articles published from 1991 to 2008 were searched, and results were subjected to meta-analysis to determine the treatment variations without any bias. Thirty factors affecting in vitro embryo production in buffalo were considered. Initially, both fixed- and random-effect models were used. We did not observe any heterogeneity between the studies. Thereafter, all the studies were pooled using the fixed-effect model for analysis. Our analysis suggested that good buffalo oocytes with more than three to five cumulus layers recovered from large-sized follicles in cold seasons when cultured in TCM-199 supplemented with serum, follicle-stimulating hormone, and cysteamine resulted in maximum maturation rate and subsequent embryonic development after insemination. The values obtained in the current study may be considered for a simulation model in establishing a cost-effective suitable method for buffalo IVF in further planned research.

Effect of type of cryoprotectant on morphology and developmental competence of in vitro-matured buffalo (Bubalus bubalis) oocytes subjected to slow freezing or vitrification

The present study examined the effects of different cryoprotectants on morphology and developmental competence of in vitro-matured buffalo oocytes after slow freezing or vitrification. After slow freezing in dimethyl sulfoxide (DMSO), ethylene glycol (EG) or 1,2-propanediol (PROH), at 1.0 or 1.5 m each, the proportion of morphologically normal oocytes recovered was significantly higher (P < 0.05) with 1.5 than 1.0 m for all cryoprotectants and was highest (P < 0.05) for 1.5 m DMSO. Following vitrification, the percentage of morphologically normal oocytes recovered was lower (P < 0.01) for 40% EG than for 40% DMSO, 20% EG + 20% DMSO or 20% EG + 20% PROH. The most common damage, irrespective of the cryopreservation method, was loss of cumulus mass. The cleavage rate and the proportion of vitrified-warmed oocytes that developed to morulae/blastocysts were significantly higher (P < 0.01) for 20% EG + 20% DMSO than for the other groups. A higher proportion of oocytes developed to morulae (11.5% v. 4.3%) or blastocysts (5.4% v. 0.6%) after vitrification in 20% EG + 20% DMSO than after slow freezing in 1.5 m DMSO. In conclusion, vitrification was more effective than slow freezing for the cryopreservation of in vitro-matured buffalo oocytes.

Effect of including growth factors and antioxidants in maturation medium used for in vitro culture of buffalo oocytes recovered in vivo

This study examined the effect of including one of two growth factors (100 ng/ml IGF-1 or 20 ng/ml EGF) in combination with one of two antioxidants (50 microM cysteamine or 50 microM beta-mercaptoethanol) in maturation, fertilization and subsequent development of buffalo oocytes. The oocytes were recovered by in vivo ovum pick-up technique from six Murrah buffalo heifers twice a week over a period of 16 weeks. Immediately after ovum pick-up oocytes recovered from six donors were allocated randomly to five different maturation treatments. The control treatment was the basic maturation medium (MM; TCM-199 supplemented with 10% FBS, 10 IU/ml LH, 0.5 microg/ml FSH, 1 microg/ml estradiol-17beta and 50 microg/ml gentamicin). The other four treatments consisted of the control maturation medium (MM) plus one combination of a growth factor and an antioxidant viz. IGF-1+cysteamine; IGF-1+beta-ME; EGF+cysteamine or EGF+beta-ME. The total number of oocytes assigned to each maturation treatment ranged from 31 to 66. After maturation in different maturation medium, media used for in vitro fertilization and subsequent development of embryo was same for all groups. Data were analysed using Chi-square test. The maturation rate observed for the growth factor plus antioxidant treatments was similar to that for the control (90.4%). The highest cleavage rate recorded in the IGF-1+cysteamine treatment (71.9%) which was significantly higher (P<0.05) than the IGF-1+beta-ME (45.2%) and EGF+beta-ME (46.4%) treatments, but not significantly differ from the control (63.8%) and EGF+cysteamine treatment (60.7%). The proportion of cleaved oocytes those developed to blastocyst stage was significantly higher in the IGF-1+cysteamine treatment (52.2%; P<0.05) than in the control (23.3%), the EGF+cysteamine (13.5%) or the EGF+beta-ME (7.7%) treatments, but did not differ significantly from the IGF-1+beta-ME (28.6%) treatment. Following non-surgical transfer of 15 embryos to 14 synchronized recipients, four became pregnant and only one recipient sustained the pregnancy as long as 4.5 months when spontaneous abortion occurred. It was concluded that supplementing the maturation medium with IGF-1+cysteamine improved the production of buffalo embryos significantly in vitro culture.

Cysteamine supplementation of in vitro maturation medium, in vitro culture medium or both media promotes in vitro development of buffalo (Bubalus bubalis) embryos

The effects of supplementation of in vitro maturation (IVM) or in vitro culture (IVC) or both IVM and IVC media with cysteamine on the yield, hatching rate (HR) and total cell number (TCN) of buffalo blastocysts were examined. Oocytes obtained from slaughterhouse buffalo ovaries were subjected to IVM and IVF. The IVM or IVC media were supplemented with 0, 50, 100 or 200 microm cysteamine. Supplementation of IVM medium with 50 microm cysteamine increased (P < 0.01) the cleavage rate and blastocyst yield without affecting the HR and TCN whereas a higher concentration of 200 microm significantly (P < 0.05) reduced the blastocyst yield but not TCN. Similar increases in blastocyst yield, without any effect on HR and TCN were observed after supplementation of the IVC medium with 100 (P < 0.01) or 50 microm (P < 0.05) cysteamine, whereas 200 microm cysteamine was ineffective. Supplementation of both IVM medium with 50 microm cysteamine and of IVC medium with 100 microm cysteamine increased the yield of blastocysts and hatched blastocyst by over 100% (P < 0.01) compared with the controls without any adverse effects on HR or TCN. The results of the present study suggest that supplementation of both IVM and IVC media improves the yield of blastocysts without compromising their health.

Isolation, follicular density, and culture of preantral follicles of buffalo fetuses of different ages

The aim of the present study was to determine the most desirable ovarian tissue section thickness to isolate preantral follicles (Experiment I), determine follicular density (follicles/mm(2) of cortex) of ovaries of fetal buffalo of different ages (Experiment II), and cultivate preantral follicles of buffalo fetuses (Experiment III). In Experiment I, ovary sections with different thicknesses (25, 50, 75, and 100 microm) had 415.0+/-285.2, 457.5+/-341.9, 585.0+/-309.3, and 685.0+/-278.8 isolated preantral follicles, respectively. In Experiment II, the follicular density of 46 buffalo fetuses with ages between 3 and 8 months was estimated to be between 0 and 7220, with means of 0.0, 2070.7+/-2190.3, 2570.8+/-1796.6, 2298.1+/-2286.5, 1277.5+/-1074.9, and 643.6+/-543.9 throughout the age range studied. The follicular density of 5-month-old fetuses was greatest, coinciding with the largest number of follicles isolated at this age. In Experiment III, preantral follicles isolated from the ovaries of buffalo fetuses aged from 5 to 9 months old were cultivated individually for 7 days in four different media: basic medium (Minimal Essential Medium (MEM), 10% SFB, kanamycin, pyruvate, glutamine, hypoxanthine) with additional ITS and FSH 0.5mg/ml (treatment 1); basic medium with FSH and EGF 100 ng/ml (treatment 2); basic medium with additional ITS, FSH, and EGF (treatment 3); basic medium supplemented with ITS and EGF (treatment 4). Integrity and morphological features, viability, and increase in diameter of follicles cultured in vitro were evaluated individually with an inverted microscope and an ocular micrometer. The results showed that follicle structure and form were maintained during culture. Growth and survival rates of treatments 1, 2, and 3 over 7 day culture were 23.25+/-17.06, 33.75+/-26.19, and 43.75+/-31.73 microm, and 31.3+/-22.7, 22.06+/-8.13, and 28.92+/-21.32%, respectively. However, neither growth nor survival was observed in treatment 4. In conclusion, this study showed that preantral follicles of buffalo fetuses can be cultured in vitro, and that FSH is essential for follicle survival.

Somatic cell nuclear transfer in buffalos: effect of the fusion and activation protocols and embryo culture system on preimplantation embryo development

The present study was conducted primarily to evaluate several factors that affect the nuclear transfer programme in water buffalos, in which relatively few studies have been performed. Embryos reconstructed with quiescent fetal fibroblasts and metaphase II cytoplasts were matured for 24 h, and activation was found to be comparatively better than in those matured for 30 h. A significantly higher proportion of embryos fused (52.0 ± 1.9) and cleaved (51.2 ± 1.7) when the couplets were fused 4–6 h before activation than when fused and activated simultaneously (46.5 ± 1.6 and 44.5 ± 2.0, respectively). Development of nuclear transfer embryos to the blastocyst stage (4.8 ± 2.2) was supported by a commercially available sequential medium, and cleavage (76.5 ± 2.8) was significantly higher in this medium compared with cleavage in TCM-199 with oviduct epithelial cell coculture (45.6 ± 1.5) and synthetic oviduct fluid (21.8 ± 6.6). Of the 16 cloned embryos transferred, none resulted in pregnancy. The present study demonstrates that optimal numbers of cloned buffalo blastocysts can be obtained from oocytes matured for 24 h, fused 3–4 h before activation and cultured in a commercially available sequential media (G1/G2), thus providing further information to enable successful nuclear transfer in buffalos.

Repeated ultrasound-guided transvaginal oocyte retrieval from cyclic Murrah buffaloes (Bubalus bubalis): Oocyte recovery and quality

The present study was undertaken to explore the potential of the Murrah breed of buffaloes as donors of oocytes and to find out the recovery rate and oocyte quality in cyclic Murrah buffaloes subjected to oocyte recovery once a week. Murrah buffaloes (n = 5) were synchronized for estrus by a single prostaglandin injection schedule. The animals were subjected to transvaginal oocyte retrieval (TVOR) once weekly for 6 weeks, starting from Day 7 of the oestrous cycle (Day 0 = day of oestrus). TVOR was performed using an ultrasound machine with a 5 MHz transvaginal transducer, single lumen 19-gauge, 60 cm long needle and a constant vacuum pressure of 50 mmHg. The number and size of follicles in each ovary was determined before puncture. The follicles were characterized on the basis of their diameter as small (3-5 mm), medium (6-9 mm) and large (> or = 10 mm). The oocytes recovered were classified as grade A, cumulus-oocytes complexes (COCs) with > or = 5 layers of cumulus cells; grade B, those with two to four layers; grade C, partially denuded oocytes; and grade D, completely denuded oocytes. The mean (+/- S.E.M) number of small, medium and large follicles, and the number of total follicles observed per animal per session, which was 2.2 +/- 0.3, 0.6 +/- 0.2, 0.9 +/- 0.1 and 3.7 +/- 0.3, respectively, did not differ between animals or between puncture sessions. Small follicles constituted a major proportion (59%) of the total observed follicles. A mean (+/- S.E.M) number of 3.0 +/- 0.3 follicles were punctured and 2.0 +/- 0.3 oocytes recovered per animal per session, with a recovery rate of 68%. Out of the total 61 oocytes recovered, 36 (59%) were of grades A + B whereas 25 (41%) were of grades C + D. In conclusion, this study describes the potential of cyclic Murrah buffaloes as donors of oocytes collected by repeated TVOR once a week, without any adverse effects on follicular growth and oocyte recovery. It also describes an efficient system for carrying out TVOR in buffaloes.

Influence of epidermal growth factor and insulin-like growth factor 1 on nuclear maturation and fertilization of buffalo cumulus oocyte complexes in serum free media and their subsequent development in vitro

The in vitro maturation, fertilization and development of Indian water buffalo (Bubalus sp.) cumulus oocyte complexes (COCs) to blastocysts were studied during culture, either in serum free tissue culture medium 199 (TCM 199) or Waymouth MB (WM). Based on different supplements added to these media, the experimental groups included: (a) no supplement (control); (b) hormones (FSH, LH and oestradiol) (c) Epidermal growth factor (EGF); (d) IGF-1; and (e) EGF + IGF-1. Experiments were conducted to note three end points: (1) nuclear maturation 24 h after culture (eight replicates); (2) fertilization 24 h after insemination (10 replicates); (3) development to blastocysts (nine replicates). The oocytes were cultured in groups of up to five per drop. Using a two-way (5 x 2) factorial model with interactions, the results were compared using generalized linear models with binomial errors and the logit link function. In experiment 1, the proportion of oocytes reaching metaphase II was higher for all the supplement treatments than the control treatment (t = 3.68, p < 0.0001). The proportion of oocytes reaching metaphase II was 74.7, 63.2, 64.7 and 81% with hormone (chi2 = 17.23, p < 0.0001), EGF (chi2 = 7.07, p = 0.007), IGF-1 (chi2 = 19.21, p = 0.002) and EGF + IGF-1 (chi2 = 33.04, p < 0.0001) supplementation, respectively, compared to 46.6% in the control (no supplement) group. Media did not have an effect on outcome. In experiment 2, the proportion of oocytes fertilized was significantly higher with hormones (31.0%, chi2 = 12.5, p = 0.0004), IGF-1 (35.7%, chi2 = 20.53, p < 0.0001), and the EGF + IGF-1 combination (49.7%, chi2 = 51.35, p < 0.0001) compared to control (16.2%). No significant effect of media was seen. In experiment 3, the proportion of oocytes that cleaved at 48 h after culturing was significantly higher for all supplement treatments compared to control. IGF-1 supplementation was the only treatment that did not produce a significantly higher rate of progression to blastocysts compared to the control. Once again, media had no effect on outcome. It was concluded that maturation, fertilization and development of buffalo oocytes were enhanced by all supplements tested. Enhancement was maximal with the combination of EGF+IGF-1. In contrast, no significant differences were found between the two types of media used.

In vitro Development of Buffalo Oocytes in Media-containing Fluids from Different Size Class Follicles

Studies were conducted to investigate the effect of supplementation of fluid from different sized class [small (SFF, < 3 mm), medium (MFF, 3-8 mm) and large (LFF, > 8 mm)] of normal and cystic (CFF) ovarian follicles in oocyte culture media on oocyte maturation rate and embryo development in vitro and to test the efficacy of follicular fluid (FF) from different size classes as a whole oocyte maturation medium. Results suggested that FF were capable of developing buffalo oocytes to embryonic stage in vitro although its efficacy was lower than that of serum. Regardless of high maturation rates after in vitro maturation (IVM) in media containing FF or IVM in whole FF, low blastocyst rates were obtained after in vitro fertilization (IVF) and culture of embryos. Follicular fluid from small follicles had significantly (p < 0.05) higher potential of developing buffalo oocytes to embryonic stage in vitro than that from medium and large follicles. Cystic FF was not capable of supporting development of buffalo oocytes in vitro.

Developmental competence and post-thaw survivability of buffalo embryos produced in vitro: effect of growth factors in oocyte maturation medium and of embryo culture system

The present study was conducted to examine the effects of supplementation to IVM medium of epidermal growth factor (EGF), fibroblast growth factor (FGF) and vasoactive intestinal peptide (VIP) along with pregnant mare serum gonadotrophin (PMSG) on oocyte maturation and cleavage of buffalo embryos (experiment 1). The developmental competence of cleaved embryos cultured in either a complex co-culture system (TCM-199+10% serum+oviduct cell monolayer) or defined media (a) modified form of synthetic oviductal fluid (mSOF) was evaluated (experiment 2). The post-thaw morphology and survivability of frozen blastocysts developed from embryos cultured either in complex or defined medium was compared (experiment 3). Aspirated oocytes were cultured in maturation medium (TCM-199+PMSG (40 IU/ml-control)) supplemented with EGF (20 ng/ml), FGF (20 ng/ml) and VIP (20 ng/ml), either alone or in combination, in a CO(2) incubator at 38.5 degrees C for 24h. Maturation rate was assessed and oocytes were inseminated in vitro with frozen-thawed sperm processed in Brackett and Oliphant (BO) medium. The cleaved embryos were cultured either in complex co-culture system or mSOF. Results suggested that EGF had more beneficial effect on buffalo oocyte maturation, and embryo cleavage than FGF. Addition of VIP to the oocyte maturation medium did not improve the results. Blastocyst yields from buffalo oocytes were significantly higher in a complex co-culture system than in defined media (mSOF) when oocytes were matured in presence of EGF either alone or in combination with FGF and VIP. The mean percent of morphologically normal blastocysts after thawing and their survivability were significantly higher in blastocysts obtained from embryos cultured in mSOF than those cultured in complex co-culture system.

In vitro maturation and fertilization of buffalo oocytes: effects of storage of ovaries, IVM temperatures, storage of processed sperm and fertilization media

Studies were conducted to examine the possibility of preserving slaughterhouse-derived buffalo ovaries at 4 degrees C for 0 (control), 12 and 24 h to maintain the developmental competence of the oocytes (experiment 1), to assess the effect of incubation temperature during oocyte maturation on rates of in vitro maturation (IVM) and in vitro fertilization (IVF) of buffalo oocytes and embryo development (experiment 2), and to examine the effect of storage at 25 degrees C for 0 (control), 4 and 8 h of frozen-thawed buffalo sperm and BO and H-TALP as sperm processing and fertilization media on cleavage and embryo development in vitro of buffalo oocytes (experiment 3) in order to optimize the IVF technology in buffalo. Results suggested that storage of ovaries at 4 degrees C for 12 or 24 h significantly (p < 0.05) reduced the developmental potential of oocytes. Incubation temperatures during the IVM influenced the fertilization rate but had no significant effect on maturation and subsequent embryo development. The incubation temperature of 38.5 degrees C during IVM was found to be optimum for embryo production in vitro. Storage of frozen-thawed sperm at 25 degrees C for 8 h significantly (p < 0.05) decreased its ability to cleave the oocytes. Sperm processed in BO medium had significantly (p < 0.05) higher ability to cleave the oocytes than the H-TALP medium.

Effect of insulin, transferrin and selenium and epidermal growth factor on development of buffalo oocytes to the blastocyst stage in vitro in serum-free, semidefined media

The in vitro development of buffalo oocytes up to the blastocyst stage was studied in serum-free, semidefined media containing bovine serum albumin, follicle-stimulating hormone (FSH), insulin, transferrin and selenium (ITS) and epidermal growth factor (EGF). In experiment 1, oocytes aspirated from abattoir-derived ovaries were cultured in eight serum-free, semidefined culture media containing different combinations of these four factors. In experiment 2, the maturation of buffalo oocytes and the development of the embryos were compared in a complex co-culture system and in the serum-free, semidefined media. Supplementation with FSH and EGF significantly (P < 0.05) increased the maturation rates of buffalo oocytes, and the yield of blastocysts was higher (P < 0.05) in media containing EGF and ITS. The yield of blastocysts was lower in the serum-free semidefined media (P < 0.05) than in the complex co-culture system.

Effects of beta-mercaptoethanol on formation of pronuclei and developmental competence of swamp buffalo oocytes

This study was conducted to determine the effect of supplementing maturation medium with beta-mercaptoethanol (betaME) on pronuclei formation and developmental competence of swamp buffalo oocytes. Buffalo oocytes were matured in TCM199 medium either with 10mM betaME or without betaME supplementation for 24h. In Experiment 1, oocytes were fixed and stained for cytological evaluation after in vitro fertilization (IVF). In Experiment 2, presumptive zygotes were cultured and their developmental competency was assessed. It was found that betaME significantly improved the proportion of oocytes that exhibited synchronous pronuclei formation (31.8+/-5.1% versus 17.9+/-3.3%, P<0.05). There were no significant differences between oocytes matured with or without betaME in their capability of developing into blastocyst-stage embryos (3.0+/-1.3% versus 1.8+/-0.9%). However, blastocysts produced from oocytes matured in the presence of betaME appeared to develop faster than those from oocytes matured in the absence of betaME (P<0.05). Cavitation of embryos from oocytes matured in the presence of betaME occurred at 156 hpi, whereas those matured in the absence of betaME occurred at 180 hpi. Although in vitro production of blastocysts did not increase by addition of betaME to maturation medium, quality of blastocysts produced from oocytes matured in the presence of betaME was improved. This study provides information for further investigations on optimizing a system for in vitro production of swamp buffalo embryos.

In vitro culture of buffalo (Bubalus bubalis) preantral follicles

Growth of buffalo preantral follicles in culture was studied to investigate the effect of size of preantral follicles, individual or group culture, long-term culture of preantral follicles for (40 days), addition of human follicle stimulating hormone (FSH), insulin-transferrin-selenium (ITS), growth factors (epidermal growth factor (EGF), fibroblast growth factor (FGF), vaso active intestinal polypeptide (VIP) in culture media, and substitution of pregnant mare serum gonadotrophin (PMSG) for FSH as gonadotrophin source in culture media. Preantral follicles were isolated mechanically from ovaries of matured, nonpregnant slaughtered buffaloes and cultured in droplets of culture media under mineral oil in a 35 mm petri dish in a CO2 incubator (38-39 degrees C, 5% CO2 in air, 90-95% relative humidity) for 15 days. Preantral follicle isolation and washing medium consisted of Minimum Essential Medium (MEM) supplemented with steer serum (10%), glutamine (2 mM), sodium pyruvate (0.23 mM), hypoxanthine (2 mM) and gentamycin (50 microg/ml), respectively. In Experiment 1, we placed isolated preantral follicles individually or in groups of 2-4 preantral follicles in 30 or 50 microl droplets, respectively, using two culture media: washing media and washing media + ITS (1%) + FSH (0.05 IU/ml), respectively. In Experiment 2, we grouped isolated preantral follicles were grouped into six different size classes: < or = 36, 37-54, 55-72, 73-90, 90-108 and > or = 109 microm. We cultured groups of 2-4 preantral follicles in washing media + ITS (1A) + FSH (0.05 IU/ml) in a CO2 incubator for 15 days. In Experiment 3, we allocated groups of 2-4 preantral follicles to 10 treatments: (1) only washing media, (2) washing media + FSH (0.05 IU/ml), (3) washing media + ITS (17%), (4) washing media + ITS (1%) + FSH (50 IU/ml), (5) washing media + ITS (1%) + EGF (50 ng/ml), (6) washing media + ITS (1%) + FSH (0.05 IU/ml) + EGF (50 ng/ml), (7) washing media + ITS (1%) + FGF (50 ng/ml), (8) washing media + ITS (1%) + FSH (0.05 IU/ml) + FGF (50 ng/ml), (9) washing media + ITS (1%) + VIP (50 ng/ml), and (10) washing media + ITS (1%) + FSH (0.05 IU/ml) + VIP (50 ng/ml). In Experiment 4, based on the results of Experiment 3, we incubated preantral follicles from those treatments showing significantly (P < 0.05) higher growth up to 40 days. In Experiment 5, we allocated groups of 2-4 preantral follicles to two treatments: (1) washing media + PMSG (50 IU/ml), and (2) washing media + ITS (1%) + PMSG (50 IU/ml) and cultured in a CO2 incubator for 15 days. The results indicated that the preantral follicles cultured in groups had a higher growth rate (P < 0.05) than those cultured as individuals. ITS, FSH, PMSG and growth factors significantly (P < 0.05) promoted the growth of the preantral follicles. Following 40 days of culture, follicular architecture was preserved in nearly 17% of the follicles though there was no antrum formation. The growth rate of preantral follicles was lower in buffalo than in cattle.

Production of buffalo (Bubalus bubalis) embryos in vitro: premises and promises

Techniques for in vitro production (IVP) of buffalo embryos adopting the procedures developed in cattle have received increasing interest in the recent times. A high oocyte maturation, fertilization and cleavage rate and a low rate of blastocyst yield and calving following transfer of in vitro produced buffalo embryos have been obtained. The efficiency of IVP in buffalo is much lower than that in cattle. Several problems need to be resolved before IVP technology can be used regularly in buffalo breeding. This review attempts to present an overview of the different techniques used in buffalo to produce transferable embryos in vitro, namely in vitro maturation and fertilization of immature oocytes and in vitro development of the resulting cleaved embryos to the blastocyst stage before transfer. The problems associated with IVP, the possible solutions and the new biotechniques linked to IVP are discussed.

Timing of sequential changes in cumulus cells and first polar body extrusion during in vitro maturation of buffalo oocytes

Studies were conducted to investigate the degree of the cumulus cell expansion and expulsion of the first polar body in relation to time of incubation in three different culture media during in vitro maturation of buffalo oocytes and to suggest a suitable practical method for assessment of in vitro maturation rate of buffalo oocytes. Buffalo oocytes were aspirated from ovaries collected from a local slaughterhouse. Only oocytes with more than two layers of cumulus cells and homogenous ooplasm were cultured into 50 microl droplets of three different culture systems: (1) TCM-199 + steer serum (10%): (2) TCM-199 + steer serum (10%) + PMSG (40 IU/ml); and (3) TCM-199 + steer serum (10%) + PMSG (40 IU/ml) + estradiol 17beta (1 microg/ml) in a 35 mm Petri dish. The droplets were covered with warm (39 degrees C) mineral oil and incubated in a CO2 incubator (39 degrees C, 5% CO2 in air, 90-95% relative humidity) for 16-18, 20, 22, and 24 h. The maturation rate was assessed by evaluation of degree of cumulus cells expansion and identifying first polar body extrusion into the perivitelline space under stereo zoom microscope. Matured oocytes were inseminated in vitro with 9-10 million sperm/ml of Brackett and Oliphant (BO) medium. Cleaved embryos were cultured in TCM-199 supplemented with steer serum (10%) for 8 days. Cumulus expansion and extrusion of first polar body commenced at 16 and 17 h, respectively, of buffalo oocyte culture. These events mainly exhibited during 22-24 h of culture. Oocytes with Degrees 1 and 2 cumulus cells expansion and extruded first polar body in degree 0 oocytes may be considered as matured and can be used in IVF studies.

Successful in vitro production of embryos in the red deer (Cervus elaphus) and the sika deer (Cervus nippon)

The aim of our study was to define the conditions for IVM and IVF of oocytes in 2 common deer species as models for endangered related subspecies. Immature oocytes were recovered during the breeding season from postmortem ovaries (red deer) or by repeated laparoscopic follicular aspiration (sika deer). Oocytes were cultured for 24 h in IVM medium supplemented with EGF or FSH and follicular fluid. Stag semen was collected by electroejaculation (both species) or by epididymal flushing (red deer) and cryopreserved. For IVF, oocytes were exposed to different concentrations of thawed spermatozoa in a modified Tyrode albumin lactate pyruvate medium supplemented with 20% (v/v) estrus sheep serum for 18 h. After IVF, presumptive zygotes were allowed to develop in vitro for 7 days in synthetic oviduct fluid (SOF) supplemented with fetal calf serum (10%, v/v). In both species, the presence of ovine FSH and follicular fluid improved the in vitro maturation rate. In the sika deer, the optimal sperm concentration for IVF was 10(6)/mL and some fertilized oocytes reached the early morula stage (20 to 25 cells). In the red deer, after IVF with ejaculated or epididymal spermatozoa (2.0 x 10(6)/mL), 20% of zygotes developed to the blastocyst stage (50 to 80 cells).